Is caffeine harmful to me?
Physiological effects of caffeine on the human body are fairly understood and
well documented. The main physiological effect of caffeine appears to be as
a stimulant of the central nervous system and most of the effects observed are
behavioural in nature. Caffeine is associated with an increase in intellectual
activity, but this seems to be significant only when the individual is fatigued
or bored. Similarly, caffeine has been linked with sleeping problems and although
there is evidence to support this, the variation from individual to individual
is considerable.
Caffeine: can it be used to our advantage?
Caffeine speeds up our metabolism (it can be found as a main ingredient in most
weight-loss products). It also increases the breakdown of fat, freeing fatty
acids, which are used in energy production during exercise. Conversion of fat
to energy is about 30% more efficient when caffeine is consumed prior to exercise.
Does this mean that caffeine burns fat? Not exactly. The caffeine-enhanced fat breakdown can only occur during exercise. While the fat is being burned, glycogen and glucose are being reserved, allowing blood sugar levels to remain higher for longer. Higher glucose levels ward off hunger. This is why coffee is popular among students and think tankers. The brain functions exclusively on glucose, and higher blood sugar levels facilitate thinking.
2000 National Coffee Drinking Trends survey
- 54% of the adult population of the United States drinks coffee every day.
- Of these, 19% drink gourmet coffee beverages every day, whether the premium
whole bean varieties, espresso-based beverages (latte, espresso, café
mocha, and cappuccino) or frozen and ice-blended coffee beverages.
- Another 25% of the population drinks coffee occasionally.
- On a per capita basis, men drink more coffee than women (1.9 cups per day
vs. 1.4 cups)
- Coffee drinkers consume an average 3.2 cups of coffee per day.
- The average coffee cup size is 9 oz.
- 35% of coffee drinkers drink their coffee black; while 62% add a sweetener
and/or creaming agent.
- 62% of all coffee is consumed at breakfast; 22% between meals; and 16% at
all other meals.
- Women are more excited about coffee varieties currently available and a higher
proportion of women indicated that drinking coffee is a good way to relax.
- Women are more price conscious than men.
- Men appear to more readily attest that coffee helps them 'get things done'.
What is the scientific consensus on coffee's safety?
Decades of research and centuries of human consumption are pointing towards
the relative safety of coffee and caffeine. According to the National Library
of Medicine, more than 19, 000 scientific studies to date have been conducted
on coffee or caffeine, and the US Food and Drug Administration still considers
caffeine to be "Generally Recognized as Safe."
In fact, recent scientific research carried out at the Mayo clinic Harvard School of Public Health, US Veterans Administration and other medical centers show that coffee is not only safe but also beneficial. Drinking from 2-4 cups of coffee a day may lower the risk of colon cancer (40%), gallstones (45%), cirrhosis of the liver (80%), and Parkinson's disease (50-80%), among other disease. It can even reduce the incidence of asthma (25%) because of the presence of chemical theophylline in coffee.
What's more, research has shown that there are four times the amount of anti-oxidants in coffee than in green tea, that coffee is an excellent anti-depressant and an effective performance enhancer, improving one's memory and energy levels for both mental and physical activities.
More on health, coffee, and caffeine intake
Moderate consumption of caffeine, defined as 2-4 cups of coffee a day, has been
found to be of no major concern. Caffeine effects are similar to those of amphetamines,
but milder. Caffeine stimulates making people feel more alert and less fatigued.
Caffeine also helps by dilating arteries, hence increasing blood flow; its effect
on arteries in the brain is to constrict, helping to counter migraines in some
cases (caffeine is also a well known cause of migraines).
Is coffee addictive?
No. Coffee drinkers do not require increasing amounts of caffeine over prolonged
periods of time (characteristics of addictive substances) and they can moderate
or change their consumption with no difficulty. Moreover, coffee consumption
does not cause psychosocial effects.
Heart health and Cancer
Early studies produced possible links between caffeine consumption and heart
disease as well as certain cancers, especially breast cancer. Better and more
recent studies have shown no support for these links, however. While high consumption
of filtered coffee may cause a slight increase in blood cholesterol, there is
no indication of direct harm, and this increase may be the result of substances
in the coffee other than caffeine. When it comes to cancer, the American Medical
Association now states that there is no relationship between caffeine intake
and any kind of cancer.
Weight Loss
Here is some good news for weight loss enthusiasts. Caffeine increases the caloric
burning rate. According to a Danish study of normal weight volunteers, one cup
of coffee has been found to raise the metabolic rate by 3-5%. This caloric burn
rate is even greater with exercise. The caffeine seems to make body fat more
readily available as fuel to exercising muscles. Muscles work longer before
they fatigue.
Blood pressure
Caffeine has also an effect on the cardiovascular system by relaxation of the
smooth muscle of blood vessels and an increase in heart output. However, the
observed increases in blood pressure disappeared after repeated ingestion of
caffeine (250mg 3 times a day for 7 days). The reasons for this adaptive process
are not clear.
Behaviour
Caffeine stimulates the central nervous system. Recent research has shown that
caffeine in moderate doses enhances alertness, well being, energy, motivation
and concentration.
Caffeine has been found to improve alertness, as well as prolong beneficial
mood effects in individuals deprived of sleep for 48 hours.
Although a few people may be particularly sensitive to any source of stimulation,
including caffeine, there is no conclusive evidence that caffeine causes symptoms
of anxiety in healthy individuals. In diagnosed panic or anxiety disorder patients,
the stimulant effects of caffeine may exacerbate existent symptoms.
Women's Issues
The US FDA recommends that women who are pregnant or hoping to become pregnant
avoid caffeine or consume as little as possible. High caffeine consumption can
make it harder to become pregnant and/or lead to miscarriage or low birth weight
infant. Since caffeine will show up in breast milk, breast-feeding mothers should
likewise avoid it. If you're concerned about your iron status, you should know
that some of the substances in tea and coffee could interfere with iron absorption,
particularly if you drink a caffeine containing beverage with your meals.
Energy
Caffeine stimulates the central nervous system, which can lead to greater productivity.
For example,
Osteoporosis problems
There is some evidence to link caffeine to a negative effect with calcium absorption.
Women who drink caffeinated products lose more calcium through urine and tend
to have less dense bones than non-caffeine drinkers. Drinking at least a daily
glass of milk for every 2 cups of coffee may offset the calcium loss.
GI health
Caffeine relaxes the valve between the bottom of your esophagus and the top
of your stomach. When this gateway flops open, stomach fluids can surge up into
your throat, causing heartburn. Also, coffee, tea, colas, and other caffeinated
products may aggravate ulcers by increasing acid secretion in the stomach (though
in fact, decaffeinated coffee has also been shown to increase acid production).
If you're prone to heartburn or have an ulcer, but still want your coffee or
tea, at least avoid drinking it with other foods that can aggravate heartburn
or ulcers such as alcohol, mints, and acidic produce such as oranges and tomatoes
(By the way, adding milk to your coffee won't soothe your stomach. Dairy products
also stimulate acid secretions).
Rest room issues
Because caffeine increases blood flow to the kidneys, it acts as a diuretic
making you urinate. However, this appears to be a problem only when you're not
exercising. Several studies have shown that caffeine consumption prior to exercise
does not lead to excessive urination and dehydration. Scientists are not sure
why. It could be that adrenaline or other substances related to exercise shut
off caffeine's usual effect on the kidneys.
Heart Arrhythmia
Heart arrhythmias are irregularities of the heartbeat. A growing body of research
indicates that the heartbeat irregularities are not affected by coffee and caffeine
consumption for the vast majority of individuals, both healthy and those with
heart disease.
Item
|
Serving
|
Caffeine
|
|
Size (oz)
|
Content (mg)
|
Brewed Coffee
|
8
|
60-90
|
Instant Coffee
|
8
|
75-125
|
Drip Coffee
|
8
|
95-150
|
Espresso
|
Single
|
100
|
Cappuccino
|
Single
|
100
|
Decaf
|
8
|
8
|
Strong tea
|
8
|
60-75
|
Weak tea
|
8
|
40-50
|
Cola
|
12
|
30-56
|
Diet Cola
|
12
|
38-65
|
Sprite/7Up
|
12
|
0
|
Chocolate
|
2
|
10-50
|
Cocoa
|
5
|
4
|
Diet Pills
|
1
|
100-200
|
No-Doz
|
1
|
100
|
Vivarin
|
1
|
200
|
Pain Relivers
|
1
|
30+
|